This competing continuation application builds on our past research on multigenerational drug use among mothers and daughters by distinguishing between different stages of drug involvement, including resistance to involvement, initiation, continuation or discontinuation, escalation or resistance to escalation, dependence, cessation, and relapse. The approach will allow for the identification of factors which determine an individual's susceptibility and resistance at each stage of drug involvement from the users' perspective. The proposed research also builds on our past work by including of a nested-family approach, which will allow for an exploration of the family domain and gender. Finally, we will supplement the predominantly qualitative data collection with quantitative measures. The specific aims of the proposed study are: (1) to examine the developmental progression of drug involvement among young adult cocaine users (the probands) and two of their first-degree relatives, including factors motivating and hindering the transition between stages of involvement; (2) to identify familial patterns of substance use among young adult cocaine users and their first-degree relatives; and (3) to explore the medical consequences of drug abuse among the probands and their first-degree relatives. The study sample will consist of 360 individuals: (120 probands, 120 biological parents, and 120 biological siblings). The data collection includes a limited quantitative component and a qualitative, in-depth interview. Quantitative assessments will cover demographic characteristics, family characteristics, lifetime and recent drug use, HIV/AIDS and hepatits B and C risk behaviors, substance abuse and selected psychiatric disorders. The interview guide will cover domains such as family of origin, family tree, life stages --including early years, childhood, adolescence, and young adulthood, drug use --including tobacco and alcohol and with a focus on the drug use career trajectory, and health --including HIV/AIDS, hepatitis B and C, and mental health, specifically anxiety, antisocial personality disorder, depression, and post-traumatic stress disorder). Qualitative data analysis involves grounded theory and quantitative analyses includes descriptive statistics, least square analysis, and confirmatory factor analysis. The proposed study contributes to the research on the origins and multiple pathways to drug abuse and of factors (individual and familial) which may determine susceptibility and resistance at the various stages of drug involvement.